MCP-4

Human MCP-4 or CCL13 cDNA encodes a 98 amino acid residue precursor protein with a 23 amino acid residue hydrophobic signal peptide that is cleaved to yield an 8 kDa, 75 aa mature MPC-4. Mature MPC-4 lacks any potential N-glycosylation sites and shares a pyroglutamate proline motif with other human MCP proteins. Human MCP-4 is most homologous to MCP1, 3 and Eotaxin, exhibiting approximately 65-66% amino acid sequence identity. The mRNA is expressed by a number of activated cell types, including endothelial cells, macrophages, bronchial epithelium and type II alveolar cells, and perhaps lymphocytes. MPC-4 is a chemoattractant for monocytes and eosinophils, and activates basophils. In addition, it has been reported to be chemotactic for CD4+ and CD8+ T cells, with an activity almost equivalent to that of MCP3. The bioactivities of CCL13 is most likely mediated by the CC chemokine receptors CCR2 and CCR3, both of which have been shown to bind CCL13.